Timing valve for track sanders



Feb. 3, 1948. H. N. SUDDUTH 2,435,372

TIIJIING VALVE FOR TRACK SANDERS Filed Jan. 26, 1945 T/M/NG BES- TD Cl/A EG/NG VA L V5 Pie. 2

lnventor (Ittornegs Patented Feb. 3, 1948 Henry 3 l lortom Sudduth,

' signor toThaNewYork Air Brake Company, a

corporationoftNew Jersey 1 H mentary opening of event valve, will thereupon T 'opertate the sander fora definite'period, and

rese

A preferred: embodiment of the invention is shown in the accompanying-- drawing, in which: Fig. 1 is a view part in elevation; but chiefly in section, showing the essential sanding-elements for one'car, in their inactive or running positions. Fig. 2 is a, fragmentary sectionlof the slide valve and seat of the timing valve, i i-sanding position. In the drawing theportingof the-timing'valve then and of the vent valve is diagrammed as if all the ports lay in a single plane. Thispermits all flows to be traced in a single view. More compact arrangements can readily be evolved and are commercially desirable. g a

To reduce the number of reference numerals and simplify description a single reference numeral is used to designate pipe s and passages which form simple cdntin'uations of one another.

A sander of knowniorm isrindicated at 5. It is supplied with air for sanding through a connection 6. Any suitable numberoffsanders may be supplied byconnection 6, which is shown with a branch for connecting one or more additional sanders (not shown). a 5 i Connection 6 leads to the timing valve gene erally indicated atl through a pipe; bracket 8 on which the body- '9 of the valve is removably mounted. a a

A sanding air reservoir II is charged through connection l2 by any suitable means, such as a charging valve connected with the air brake system. The reservoir II is inscommunication with the timing valve through connection [3.

'A timing reservoir l4 serves to enlarge the volume of the slide valve chamber. in the body 9, with which it communicates by connection IS. The interchange of reservoirs of di'fierent size offers means for primaryfs'etting of the-timingperiod. I a

The timing valve is connected by connection ll with the electro-pneumatic vent valve generally indicated at l8.

The valve chamber I5 is formed by a valve seat bushing I9 pressed into body 9 and communicating at one end with a larger cylinder 20. A plug 2| closes one end of the slide valve chamber and a cap 22 closes the open end of the cylinder 29 so that a control chamber 23 is formed at the outer side of the piston 25. The cap is sealed to V Application-lan r! 2 5;: Ser aLN, r l 2Claims. (01. 291 -3) the body'by a gasket, which also offers a sealing seat for the piston 25. Piston 25 works in the cylinder 2!] and'lhas a stem 26 guided in valve 'chamber 1 5 byspider 21. The piston has a packing ring, as shown, and the stem 2B' has a notch in which the' slidevalve 28 is receiv'ed so as to be reciprocate'd by the stem without substantial lost motion. 1

A coil compression spring 29 seated in sockets in piston 25 and cap 22 biases the piston inward. The depth of the sockets is such as to permit use 'of asprinig' ofconsiderable length, so that the force resisting motion ofthe piston outward will not buildup too rapidly. Inward motion of the piston is limited by collision with the end of bushing 19', which is'riotched-as shown to permit'air 'flow. r

A can 3| attached toth'e' top of body 9 clamps themargin of diaphragm 32. v A strut 33, con nected to the center of the diaphragm reacts on the back (top) 01E lide valve 28'. Thestrut is loaded by a coil compression spring 34 and also by thejair pressure in reservoir H reacting on diaphragm 32 through'a branch of passage l3. This prevents the valve iromever being blown from its seat. H

he seat for slide "valve 28 is formedin bushing 19 and has six ports. The related slide valve has two cavities and one through port, allof which are identifiedby numbers applied only to Fig. 2. The ports in theseat are a timing port 35, which: leads to atmosphere through an interchangeable choke 36; a restricted charging port 3fl leading irom passage l3; a controlling port 33' connected to passage H which also communicates with c'ontrol chamber 23 at the outer side of piston 25; an exhaust port' 39; a sander port 4llcomihunicatin'g with passage}; and areservoir; port 42 fedby passage l3. Theinterch'ange of different sizedchokes 36 is the means usually availed of to change timing. If'a long period requires the use of an undesirably small choke a larger reservoir l4 may be s1'J'.bstitute'dl a Y The slidevalve 'hascavi'ties 43 and 44 and a restricted through port45arrang d as shown,"so that in running (non-sanding) position the timing port 35 is blanked; ports 31 and 38 are connected by cavity 43 to charge control chamber 23; ports 39 and 4| are connected by cavity 44 to vent the sanders and ports 42 and 45 register to charge valve chamber 15 and timing reservoir l4. With the system charged, venting of connection I! causes venting of control chamber 23. The air pressure in chamber l5 then forces the piston to v 3 the right overpowering spring 29. This shifts valve 28 to the position of Fig. 2 in which: port 35 is exposed and serves to bleed down the pressure in valve chamber I port 31 is blanked; port 38 is connected to exhaust port 39 by cavity 43 so that control chamber 23 is maintained vented causing piston 25 to remain in its outer position-untilapressurein chamber Hiis nearly completely dissipatedy" portu 42 supplies air through cavity 44 to sander port 4| to operate the sander. from reservoir ll, giving sustained. action until the valve 28 is shifted back by'spring'i'flfas'it will be when the sipated. .1 z' zeg. While connection I! may be controlled vented and closed) by various means, the ferred mechanism is an electro-pneumatic such, for example, as that shown at IS in for which per se no no elty is here claimed. or The main valve elementzista-diaphragm 46 clampedat its-xperiphery-between-body-41 and cap:,48-,- and biased! toward. seat 49 by -coil compression 1 springlfi l wThB seat-=49 controls an exhaust passage 52 a; i M'I'heannularzspace; 53 on the inner side of diaphragm 46 ;is in freecommunication with passage l l and when the diaphragm is forced to the .right space,53=isrconnected to atmospherel. .w-Aanormallyrdeenergized solenoid 54 operates a double-beat poppetgvalveii, -so arranged that whenthe solenoid is deenergized, space '53 is connecteduwith. the -spaceaon the-outer'side of dia phzragm 46. Since/pressures acting on thediaphragm are equal springitholds-thediaphragm against seat :45. When, however, the solenoid is energized it shifts valve 55 so that it disconnects theserspaces'andt connects the space on the outer side. of; ether diaphragmto t atmosphere. Pressure in space-.-53:unseatsitherdiaphragm so that space 153 and:passage: t1 are vented. :Venti-ngofpassagexlilsentails venting of controhchamben 23,-.so-,that piston 25.movesv.to the right shifting slide tvalve :2-8.-.- to the position of Fig-a2.-:=:Inzthis-position air is suppl-ied .to. the sanders, but bleeding of chamber I5 and reservoir prevalve 4 4i .commenoesmand finallyallows -.--spring .29 to restore: piston 252andevalve: 28. Bythis--time soleneidaw will-have beendeenergized; The-ports are .sodimensioned and spaced that'as the: valve 28moves to the: left port ,BJwill recharge connection.1I:and-.all;communicating spaces, particularly -the.contro1.=chamber '23; somewhat in-advance-nof-rthe recharging of-cha'mber I5. by vport 45".and'beforeefinaliclosure of the port 35. ,-This ensuresthat the valve. -28 -will move full stroke and not..-stallin an intermediate position.-

a V It. shou1d;be'-observed that once-piston 25 has shifted outward it"is-self-retaining until valve I chamber I S and: reservoir l4.- have-beenbled pressurelin chamber. v4 5. .is. dis-.

Observe that all sanding air comes 7 -tional equivalent.

Observe also, that any means which will cause piston 25 and valve 28 to shift to sanding position will initiate the sanding cycle, and that the piston will hold the valve in sanding position for the desired period. Hence various substitutes for valve [8 are possible.

Any means, manual, or automatic, may be used toeontrol energization of solenoid x54 or its func- Thus :the mechanism is well adapted for association with brakes, wheel-slip Ldetectors and similar devices heretofore proposed as means for controlling sanders.

' thesander with saidisource andaifords alarge through choke 36." .It is thus out of the control of -.'th'e.vent.valve. [8 during the-timed sanding period; Consequently-the precise time of. reset ting of valve is is not important. Even'a second actuation of valve J8 while sanding isaproceeding canvhavemo disturbing'eifect.

" *Whatisclaimed is:

--1.:The combination of a an air: operatedasander source of sanding air; means forming a slide L: valve -"ch'amberpz'an expansible chamber motor having a movable abutment subject on one side topressure in the valve chamber and on the other sidezzto pressure in a control chamber; a ported slide valve coasting with a ported seat in the chamber and connected to beshiftedbyr'said abutment between an inward running position in which it vents the-sander =and 'chargeswbothithe valve chamber and the control chamber from said source, an :outward sanding position in which it connects the sanderwithsaid source and aifords a large capacity vent from the control chamber anda restricted vent from-thevalve-"chamber andan intermediate position in which it-charges the control chamber without charging-.the valve chamber means biasing the abutment and valve inward toward running position; and ;means for causing said abutment and valve-to shiftfrom running to sanding position. I i ...2,..'Iiheecombinationof-a-source of sanding air; an air operatedsander; valve chamber; an; =expansiblechamber; motor havingia movable abutment subject onone side to pressure in the. valvechamber and onthelother side to pressure in a control chamberp ported slide valve coactingwith-a p0rted=seat .-in the chamber. and connected. to.--be-shifted-by s-a-id abutment between an inward running positionin which. it vents the sander and=charges boththe valve chamber and thecontrol .chamber from said source, anoutwardposition in which itconnects capacity vent from. the control chamber andea restricted ventv from the valve chamber andan intermediate position in which it-charges the controlchamber and-vents the valve chamber at; at 188513, a restricted rate means biasi-ngthe abutment and valve inward-toward runningposition; and independent means for venting theycontrol chamber atwa .rate which. exceeds the charging rate thereof in running position" I HENRYvNORTON sunburn; I a

s maenetsiemb The following references are of record in the file of: this patent:-

means forming a,slide 

